Method and apparatus for manufacturing strip



March 3, 1942. E. D. SPANGLER METHOD AND APPARATUS FOR MANUFACTURING STRIP Filed Jan. 15, 1941 Patented Mar. 3, 1942 OFFICE METHOD AND APPARATUS FOR MANU- FACTURING STRIP Earl D. Spangler, Gary, Ind. Application January 15, 1941, Serial No. 374,596

2 Claims.

This invention relates to a method and apparatus for manufacturing strip and more particularly to magnetic strip material such as steel, although not limited thereto.

It is a well known fact that steel strip is of varying thickness in cross-section with the center portion thereof preponderantly heavier. This is especially true as the width increases to, for example, 36 inches and upwards. This condition is principally caused by the distortion of the metal-working rolls of the mill in which the strip was rolled, the said distortion being due to the tremendous screw-pressures applied to the necks of the metal-working rolls during the reducing operation. For example, a steel strip 36 inch-es wide and having an average thickness of .010? inch (31 gauge) so varies in its cross-sectional thickness that it is .0002 inch thicker at a point one inch inwardly of its edges than it is at said edges; and .0005 inch thicker at the center of said strip than it is at said edges. Such steel strip is usually furnished in the form of a coil having a center opening approximately inches -in diameter with the wrappings or convolutions totalling approximately 8 inches in thickness. Theoretically, such a coil would comprise "(48 convolutions or layers.

It is frequently desirable to furnish steel strip of the class described in narrow widths and for this purpose resort is had to slitting operations. Accordingly, when the coil is unwrapped and slit to narrow widths, it is found that the center portion of the coil, when rewound into a coil after slitting, increases in diameter to the extent of, for example, the hereinbefore increased thickness of .0005 inch multiplied by the number of convolutions or layers on both sides of the center opening; representing an increase of .7880 inch.

It is, of course, most expedient to rewind the slit coil as a unit, and as a result thereof the diameter of the slit center portion of the coil gradually increases in proportion until the entire strip has been rewound, thereby presenting difficulty while attempting to rewind the several portions of a'slit coil on a single mandrel. As the rewinding mandrel is, for example, operating at a speed of 100 revolutions per minute, the increase of the slit center portion of the coil at the end of the rewinding operation will, for the specified instance given hereinbefore, amount to approximately 20 feet per minute. The other portions being slit from the coil at the same time also assume diameter changes to a lesser degree due to the fact that the extra thickness inherent in the cross-section of the strip gradually diminishes toward the outer edges as aforesaid.

It is among the primary objects of the present invention to rewind in a single operation the slit portions of a strip without encountering the difficulties inherent in prior art practices.

Another object is to so accumulate the slit strips that the rewinding thereof is effected Without encountering different linear speeds.

To the accomplishment of these and other desirable objects and purposes, I have designed the present, preferred embodiment of the invention presented in the accompanying drawing forming a part of this specification and to which reference should be had in connection with the following detailed description, and in this drawing, for simplicity, like reference numerals have been employed to designate the same parts throughout the several views.

In this drawing:

Figure 1 is a longitudinal section taken in a vertical plane and disclosing a form of apparatus constructed in accordance with the teachings of the present invention, and

Figure 2 is an enlarged plan of a portion of the apparatus of Figure 1.

Referring more particularly to the drawing, wherein there is illustrated a preferred embodiment of an apparatus constructed in accordance with the teachings of the present invention, the numeral 2 designates an unwinding reel which is adapted to' receive a coil 3 and which may be motor-driven in any suitable manner (not v shown).

Disposed somewhat adjacent the motor-driven unwinding reel 2 is a motor-driven slitting shear, generally designated at 4, which comprises the customary superposed horizontal shafts carrying thereon slitting disks spaced at suitable intervals. Disposed between the unwinding reel 2 and the slitting shear 4 is a space 6 within which strip being fed therebetween may be made to assume a catenary loop, the extent of which is governed by the control of the speed of the unwinding reel 2 through an electrical switch 8 comprising a roller 9 which is disposed in the path of, and adapted for contact with, the lower portion of the said catenary loop. It is believed that the control of motors for adjusting the speed of travel of strip through a switch operated by a catenary loop is so well understood in the art as not to require illustration of more than a schematic representation of the switch per se, and accord ingly the drawing in the present instance are, in the interest of simplicity, limited thereto.

vided a space [2 within which the slit strip may assume the form of a catenary loop. In advance of this second catenary loop, and immediately 4 adjacent the pinch rolls l, there is provided a scrap collecting guide I4 for the purpose of diverting the trimmed side edges of the slit strip to a suitable depository IT. The remainder of the slit strip is directed over a guide plate 15.

The guide rest ll referred to hereinbefore is composed of a suitable relatively soft material, such as wood, and assists inguiding the slit strips into a side-guiding device 20 whichcomprises a number of idler rollers 2| of suitable material which are positioned in alternate planes above and below the normal pass line, thus subjecting the strip to a flexing action and causing it to assume a wavy form with a corresponding increase in stiffness'and length of the strip edges for contact with stationary side-guiding plates 22. The side-guiding plates 22 are suflicient in number and so disposed with respect to the edges of the slit strip as to keep separate the individual strips. Disposed adjacent the outlet end of the guide device generally designated at 20 is an electromagnet 25 which is faced with a suitable soft material 26. is 'electromagnet 25 is so energized that a magnetic flux holds the under surface of the slit strips in intimate contact with the facing material 26 which is of such composition as to prevent the scratching thereof. Preferably the electromagnet 25 is so constructed and operated that the flux density may be controlled.

After the slit strips pass over the electromagnet 25, they are passed between a pair of superposed rolls 29 which are interconnected in any conventional manner to a drag mechanism (not shown). This drag mechanism may, for example, be an electrical generator whose output can be regulated, or any mechanical, hydraulic or other means which will retard the rotation of the rolls. Referring more particularly to Figure 1, it will be perceived that as the slit strips are directed over and emerge from the electromagnet 25 they are directed onto the top of the upper roll 29, wrapped therearound for an angle of approximately 180 degrees and directed onto and around the lower roll 29 for approximately the Between the guide rest II and the pinch rolls I0 there is proformerly experienced in attempting to compensate for the variations. The electromagnet 25 also causes the strips to conform closely to the curvature of the upper rolls 29, thus aiding the resultant tension derived. This small restraining influence applied to the strips by the electromagnet 25 results in a snubbing effect, causing them to be pulled tightly against the upper of the rolls 29 and thus preventing slippage between the strips and the said roll. I

The tortuous winding of the slit strips around the rolls 29 establishes a sufliciently large cumulative friction areas as to impart to the slit strip the desired tension.

While I have shown and described specific embodiments of the present invention, it will be understood that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention as defined by the following claims.

I claim:

1. The method of manufacturing magnetic strip which includes slitting a coil of substantial width into a plurality of strips of lesser width,

accumulating portions of each of the slit strips in an untensioned state, passing said strips through a magnetic flux, pulling said strips out of said magnetic flux and around a pair of spaced-apart rolls, and coiling said strips on a single mandrel.

2. Apparatus'for manufacturing magnetic strip comprising means for slitting acoil of substantial width into a plurality of strips of lesser width, means for accumulating portions of each of the slit strips in an untensioned state, magnetic means for restraining the forward movement of the slit strips, means for pulling the slit strips 

